dnslib

Warnings

• deprecated The dnslib library is in maintenance mode and no longer undergoes active development. While minor bug fixes may be applied, significant new features or major architectural changes are not expected. Users should factor this into long-term project planning.
  Fix: Be aware that new features are unlikely. For active development or a different approach, consider alternatives like `dnspython`.
• breaking Python 2.7 support has been officially dropped. Version 0.9.24 was the last release to support Python 2.7 and Python <3.7. Later versions require Python 3.7+ (though the 0.9.25 release notes refer to 'Python2 support' in the context of maintenance mode for users reliant on the old API).
  Fix: Migrate your application to Python 3.7 or newer. If Python 2.7 support is strictly required, pin the `dnslib` version to `0.9.24` or earlier.
• breaking Significant API changes occurred around version 0.9.0 and were further referenced in 0.9.25. Specifically, the 'Bimap' interface for lookups changed, and hostnames are now returned with a trailing dot by default (RFC compliant). Updating from older `dnslib` versions might require code adjustments for these interface changes.
  Fix: Review your code for usage of the 'Bimap' interface and hostname parsing/generation logic. Consult the changelog or source for exact API differences if migrating from very old versions.
• gotcha There's a reported issue (Issue #76) where RFC2136 delete UPDATEs are parsed differently between versions. Version 0.9.24 would parse them with `rdata=''`, while 0.9.25+ rejects them, raising an error. This can affect specific DNS update operations.
  Fix: If your application handles RFC2136 delete UPDATEs, test thoroughly after upgrading to 0.9.25+. You may need to adjust your error handling or packet construction/parsing logic for these specific types of updates.

Install

• pip install dnslib Install latest version

Imports

• DNSRecord

  from dnslib import DNSRecord, DNSHeader, DNSQuestion, QTYPE, RR, A, CNAME, MX, NS, SOA

• *

  from dnslib import *

  While `from dnslib import *` is often seen in examples, importing specific classes is generally better practice. The `dnslib.dns` submodule is part of the package structure, but the core classes are typically exposed directly under `dnslib`.

Quickstart

This quickstart demonstrates how to construct a basic DNS A-record query and how to parse a (simulated) DNS response packet. It also shows a minimal example of how to create a reply to a query. Key classes like `DNSRecord`, `DNSQuestion`, and `QTYPE` are used for this.

from dnslib import DNSRecord, DNSHeader, DNSQuestion, QTYPE, RR, A, CNAME
import binascii

# --- Example 1: Creating a simple DNS A query ---
q = DNSRecord(q=DNSQuestion('example.com', QTYPE.A))
print('--- DNS Query (example.com A) ---\n', q)

# Pack the query to wire format
query_packet = q.pack()
# print(f'Wire format: {binascii.hexlify(query_packet).decode()}')

# --- Example 2: Parsing a DNS response (simulated) ---
# Example DNS response packet (e.g., for google.com A record)
# In a real scenario, this would come from a network socket.
# d5ad818000010005000000000377777706676f6f676c6503636f6d0000010001c00c0005000100000005000803777777016cc010c02c0001000100000005000442f95b68c02c0001000100000005000442f95b63c02c0001000100000005000442f95b67c02c0001000100000005000442f95b93
# A simplified, small response for 'test.com' to 1.2.3.4
# Real packets are more complex, this is just for demonstration.
response_hex = b'\x01\x00\x81\x80\x00\x01\x00\x01\x00\x00\x00\x00\x04test\x03com\x00\x00\x01\x00\x01\xc0\x0c\x00\x01\x00\x01\x00\x00\x00\x3c\x00\x04\x01\x02\x03\x04'
response_packet = response_hex

# Parse the response packet
try:
    r = DNSRecord.parse(response_packet)
    print('\n--- Parsed DNS Response (test.com A to 1.2.3.4) ---\n', r)
except Exception as e:
    print(f"Error parsing response: {e}")

# --- Example 3: Creating a reply from a query (simplified) ---
q_example = DNSRecord(q=DNSQuestion('host.example.com'))
reply = q_example.reply()
reply.add_answer(RR('host.example.com', QTYPE.A, rdata=A('192.168.1.1')))
print('\n--- Simple DNS Reply ---\n', reply)